Jan van Sol, of Danzig, West Prussia, came to Brussels, Belgium, in 1550, and visited Viglius van Aytta, chief president of the (Spanish-Catholic) Privy Council, and suggested a policy of combating Anabaptism, in which he would assist by checking that the newborn children were baptized and that no one in the Netherlands be allowed to move to another town unless provided with a certificate issued by the priest of his home church. If this project had been adopted, Mennonitism would have had a hard struggle, but Viglius distrusted van Sol. So he was put on trial. Van Sol was found to have at his disposal valuable information about the Mennonites. The Court of Holland, whose advice had been asked, opposed the project, fearing that it might seriously injure Dutch trade. So van Sol's plan miscarried. Moreover Jan van Sol proved not to be very reliable. It was revealed that he had lived at Dordrecht, Dutch province of South Holland, where he had kept an inn. In 1530 he fled to Danzig, Prussia, for safety because of his many debts. At Danzig, where he called himself Johann (Jan) Solius, he had a prosperous business. In 1536 he left Danzig and bought the "Robitten" estate near Bardeyn in East Prussia. For a time he seems to have been a Melchiorite and even perhaps a member of the Danzig congregation. He later returned to Danzig and to Holland to win converts, and was apparently successful. But he had little influence among the Mennonites, who considered him untrustworthy. By 1550 he was no longer a Mennonite. He may have spent his last years from about 1556 in the territory of Preussisch-Holland. Mannhardt's assumption that he was a physician is probably untenable.